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Oil Smoke on start up after 2 hours on rebuild; Bad Valve Guide seals from Dealer?


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17 replies to this topic

#1 RallyKeith

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Posted 21 November 2013 - 09:32 AM

I bought an '05 Legacy 2.5 with 161k and a knock. Tore the engine apart and found a bad main bearing and a pretty warn rod bearing. Rebuilt the motor but never touched the pistons or cylinders. When we split the block we left the piston assemblies in. Bought an engine gasket kit from subaru and rebuilt everything else. I was very careful, at least I thought, to follow the factory manual and installed the green seals on the exhaust valves and the gray seals on the intake valves.Everything was fine on first startup where I let the engine run for about 15 minutes at idle to bring everything up to temp. Let it cool for about an hour, then started it and drove it 15 minutes to let it set over night. Started it the following morning and drove it an hour to work. No issues during any of this. Drove it back home another hour and ran a few errands last night. This morning I started it up and got a big cloud of oil smoke out the exhaust. Shut it down and checked the oil and it was about 1/4 quart low. Drove it the hour to work and never saw obvious smoke. This screams valve guide seals to me but I wanted to get some other opinions, and even ask if anyone has ever had any follies when replacing the seals or even had bad ones from the dealer.

 

Thanks,

Keith 



#2 grossgary

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Posted 21 November 2013 - 10:07 AM

1.  you used Subaru seals it appears?  (not that i know if it matters)

2.  are you positive you got the right seals (they didn't change between the non-VVT and VVT changes from 04 - 05?)

 

assuming correct parts and installation my first thought is if the two are connected - bad bearings and valve stem seals.  which makes me wonder:

a.  is it possible for loose enough bearings to cause the pistons to have more play, extend further, and contact the valves?

 

i've seen bent valves that look so close to straight that i've just scrapped them and replaced them in fear of accidentally mixing up known good valves and bent ones. it would be easy to not notice a bent valve.  but then if it's not noticeable it doesn't seem like it would be enough to harm the guides/seals any time soon.

 

and i still can't imagine it being enough though, it seems the bearings would get worse quicker than the valves would hog out the valve guides.

 

so it seems unlikely, but so does two issues happening like this.

 

i've never had an issue with Subaru valve stem seals but they're tiny size in tight places does seem like it could lend itself to mis-seating them?

 

if you remove the two lower engine mount nuts and upper pitch stopper and jack the engine up it's easy to pull a head with the engine insitu, so you don't have to yank the motor again.



#3 RallyKeith

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Posted 21 November 2013 - 10:40 AM

Gary, the '05 motor is a one off. It did not get the VVT. As for the valves being bent I don't think so. I re-lapped them and checked a few with prussian blue and everything looked fine. Also absolutely no evidence of there ever being any interference. If I didn't get all of the lapping/grinding compound out of the valve stem tubes, could that have caused them to fail? I ran a pretty good brush through each tube with water (water based grinding compund) when cleaning up.

 

I used a seal kit from subaru. There was a small concern because it came with the wrong exhaust manifold gasket and was missing the spark plug tube seals but the kit part number was what is in the subaru system and my local dealer said they have seen a few kits come in with small mixups like that. They also said the thought pretty much all the valve seals were identical across most engines.



#4 ivans imports

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Posted 21 November 2013 - 11:27 AM

The piston oil ring oil feed hole should have been cleaned out and new rings this is your problem in those years they use very thin oil rings and they plugup badly try a cupple oil changes in a row may fix it or rering it. Oil burning was a big problem on those years oil rings just to small



#5 ivans imports

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Posted 21 November 2013 - 11:28 AM

Valves seals all same on ejs but doubt is valves



#6 grossgary

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Posted 21 November 2013 - 11:31 AM

i would guess it's easy for one of those seals to not seat properly, i know it's happened to others on the forum.

 

rings would also be a concern - i'd do a leak down test to confirm where the breach is.

 

i haven't seen it myself, so i don't know the validity of such statements, maybe they're just an artifact of old, but folks often say "fresh heads result in more compression and blow by/oil loss from rings". 



#7 ivans imports

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Posted 21 November 2013 - 11:34 AM

even with no valve seal would be minor smoke the ea81s proved this as they ran no ex valve seal valves dont make it burn oil rings do



#8 RallyKeith

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Posted 21 November 2013 - 11:38 AM

Thanks for the input guys. My first steps will be compression and leakdown. Car didn't show any signs of this issue before the rebuild. It was being driven by the previous owner and I had put about 25 miles on it before deciding it had to be rebuilt right away. My gut says I screwed something up with the valve seals since the smoke was only there after it sat overnight. Rings don't let oil leak into the cylinder while parked. When I get home tonight I may rotate the crank so that all the valves are closed, let it sit, and then pull the intake manifold off to see if there is oil pooled up on valves. That would be a sure indication of it being the valve seals.



#9 RallyKeith

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Posted 21 November 2013 - 11:40 AM

even with no valve seal would be minor smoke the ea81s proved this as they ran no ex valve seal valves dont make it burn oil rings do

 

With no seals on the intake it will suck oil when the motor is in vacuum. I've got a miata with bad valve guide seals that blows a huge cloud of smoke after I coast down a 1 mile hill in 5th gear on my way home. As soon as I step on the gas all of the oil that's been being sucked in while in vacuum ignites.


Edited by RallyKeith, 21 November 2013 - 11:41 AM.


#10 grossgary

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Posted 21 November 2013 - 12:49 PM

it does seem statistically more likely that it's something invasive that you worked on - which would be valves.

 

But I've always wondered so now is a good time to ask - being horizontal, do Subaru valves pool oil like other vehicles?  It seems like they wouldn't.

 

Oil would pool in the bottom of the cylinders behind the rings though...?



#11 RallyKeith

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Posted 21 November 2013 - 01:12 PM

it does seem statistically more likely that it's something invasive that you worked on - which would be valves.

 

But I've always wondered so now is a good time to ask - being horizontal, do Subaru valves pool oil like other vehicles?  It seems like they wouldn't.

 

Oil would pool in the bottom of the cylinders behind the rings though...?

 

Good point Gary... Now I'm thinking twice about it. 

 

Here is another interesting thing, I just checked the oil level over lunch. I've got a nice level parking lot and the car was sitting for 4 hours and the oil shows as being just a bit over full. Front of the dip stick is right on the dot and the back is just past it. I'm wondering if I had it overfilled enough from trying to prime the pump that I upset something or if it made the level high enough to pool up behind the piston as suggested?



#12 Gloyale

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Posted 21 November 2013 - 01:21 PM

Did you install a new o-ring on the oil pan where the PCV return meets the case?

 

I've seen engines burn oil badly after pan reseals when no o-ring is installed.  PCV sucks up oilly air from near the bottom of the pan.....instead of that tube being sealed and submerged to where oil can fall down it, but the PCV can't suck it up the tube.  Kinda like a P-trap to keep Sewer gasses from coming up the sink drain.

 

Just a thought.

 

Could also be oil pooled against back of piston if it was overfull 



#13 RallyKeith

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Posted 21 November 2013 - 02:42 PM

There was a seal on that tube in the pan, but the pan was an aftermarket pan. The original was heavily rusted. Since it was rusted so badly and filled with metal bits from the bearing that failed I chose to just buy a new one. Fit and construction seemed fine.



#14 Quidam

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Posted 21 November 2013 - 02:57 PM

Just some thoughts. Smoke on cold start, valve seals...you know, the valves angled up. EA81 valves come straight out the head, no angle. However, at least a good cleaning of the piston and rings would have been good.

 

And yes, a fresh valve job that now seals tight can and will put more pressure on the used rings. The old rings and valves aged together and are both not what they once were.

 

I'd check the seals on the valves pointing up at an angle.

 

Doug



#15 ivans imports

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Posted 22 November 2013 - 11:08 AM

Down hill yes start up mabee slightly for a few seconds but lots of oil and not stoping smoking rings. Ex get alot of damaged valve engines 3 or more bent valves even runing on 2-3 cly valves bent guides seals damged no smoke just pop pop pop out the ex yes a bad valve seal or guide / valve could cause oil burning but not alot just minor oil burning. When they sitt over night if rings are bad at all the oil slips past the lower part of oil ring and gets on top of piston so when you start in morning puff o smoke.



#16 darsdoug

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Posted 28 November 2013 - 06:59 PM

i would guess it's easy for one of those seals to not seat properly, i know it's happened to others on the forum.

 

rings would also be a concern - i'd do a leak down test to confirm where the breach is.

 

i haven't seen it myself, so i don't know the validity of such statements, maybe they're just an artifact of old, but folks often say "fresh heads result in more compression and blow by/oil loss from rings". 

Yes, new HG's will in fact raise compression to a point where the piston rings need to be up to snuff. I'm old school and I received most of my knowledge from a seasoned auto mechanic while helping out at a Texaco gas station in Seattle back during the summer of 1967. Last summer I helped my son-in-law put new Six-Star HG's on his 99 OB along with all new valve seals and machine surfaced heads. The EJ25D only had 136K on it but it's been going through a fair amount of oil . We determined there was no smoke coming from the tail pipe plus no oil dripping anywhere, so we've been at a loss as to where the oil was going? My guess is the rings?



#17 Subruise

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Posted 29 November 2013 - 12:39 AM

when i redid the hgs on my ea82 i removed the pistons , and ring. they were cleaned and re installed. i noticed an increase in oil consumption with no apparent source. I also deduced this as being a fault in the rings, its the only thing i didnt replace in the wear item department. (short of splitting the block of course....cmon its an ea82)



#18 Bushwick

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Posted 30 November 2013 - 03:10 AM

The EJ25D only had 136K on it but it's been going through a fair amount of oil . We determined there was no smoke coming from the tail pipe plus no oil dripping anywhere, so we've been at a loss as to where the oil was going? My guess is the rings?

 I know in other cars it's *possible* for oil to get pulled up and into the brake booster. Can't remember if a bad check valve is culprit or not, but it's easy to figure out if oil is in there or not with a long skinny rod or similar.






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